6.71ct Natural Cobalt Spinel | Massive Tanzanian Cushion | Untreated COBS27

A Geological Phenomenon: The Titan of Cobalt Blue 

In the elite world of colored gemstones, a 6.71-carat Natural Cobalt Spinel is not merely a rare find—it is a statistical impossibility. While the majority of cobalt-bearing spinels are found in sizes well under one carat, this massive Tanzanian specimen stands as a titan of its kind. Radiating an intense, electric cobalt blue that rivals the most storied Kashmir sapphires, this gemstone possesses a magnetic presence and a vibrant "neon" glow that remains undiminished even in low-light environments.

Why This 6.71ct Cobalt Spinel is a Generational Investment

• Unprecedented Museum Scale: Finding a Cobalt Spinel exceeding 6 carats is a once-in-a-decade event. This stone is a primary target for serious collectors and high-jewelry houses.
• Vivid "King Blue" Saturation: The stone’s color is fueled by natural cobalt trace elements, resulting in a rich, saturated blue that is both authoritative and mesmerizing.
• 100% Natural & Untreated: In an era of heat-treated and diffusion-enhanced stones, this spinel is entirely untouched, preserving its organic geological value.
• Authentic Tanzanian Pedigree: Sourced from the legendary mines of Tanzania, an origin synonymous with the world’s most vibrant and crystalline spinels.
• Masterful Cushion Faceting: The 11.4mm wide cushion cut provides a deep, voluminous look and an "Excellent" luster that ensures maximum light return.

Gemstone Specifications

• Weight: 6.71 Carats
• Dimensions: 11.4 x 10.9 x 7.3 mm
• Color: Intense Cobalt Blue
• Clarity: SI (Slightly Included – A natural characteristic of cobalt-bearing crystals of this immense size)
• Shape: Cushion Cut
• Luster: Excellent
• Origin: Tanzania
• Treatment: 100% Natural (None)

The Crown Jewel of Your Collection For the discerning collector who demands rarity, scale, and prestige, this 6.71ct Cobalt Spinel is the ultimate acquisition. Its sheer size and vivid saturation make it a legacy asset that will be the centerpiece of any vault or high-jewelry masterpiece. Seize this rare opportunity to own one of the world's most significant natural blue spinels. Enquire today.